An electric dipole consists of a pair of equal but opposite charges

[needingtoknow]

Homework Statement

An electric dipole consists of a pair of equal but opposite charges, +Q and -Q separated by a distance d. What is the electric potential at the point that's midway between these source charges?

Through using the formula electric potential = kQ/r, I found the electric potential at P to be 0. Electric potential is the amount of potential energy each coulomb of charge would possesses in an electric field right, so then why is it 0. If I place a negative charge at Point P, won't it be attracted to the +ve charge and repel by the negative charge. Won't it use potential energy to accelerate towards the +ve charge?

 

[haruspex]

I found the electric potential at P to be 0. Electric potential is the amount of potential energy each coulomb of charge would possesses in an electric field right, so then why is it 0. If I place a negative charge at Point P, won't it be attracted to the +ve charge and repel by the negative charge. Won't it use potential energy to accelerate towards the +ve charge?

You're confusing potential with gradient of potential. The field is the gradient of the potential, and this is what causes the force on a test charge.

I don't like the question, though. Potentials are not absolute. It's only potential difference that matters. You can take the potential at any point to be your reference potential (zero) and measure all other potentials in relation to it. The question only works if you specify also that the potential at infinity is zero.

 

[needingtoknow]

Does it matter that the point is 0 V only relative to other points as well. I don't think I am asking the question correctly, so I have attached a picture of the question which has the diagram too. It is part b).

 

[haruspex]

Does it matter that the point is 0 V only relative to other points as well.

Not exactly sure what you are asking there.
There is nothing special about 0V, it's an arbitrary reference point. As the attachment states, what matters is potential difference, i.e. the difference in voltage between two points.

The attachment says the diagram shows "the electric potential at various points in the field they produce". That's a little misleading, because you could add some constant to every value and it would be effectively the same. On the other hand, it is customary to set the 0 V level as the potential "at infinity", which is perhaps assumed here. Or, equivalently, you could interpret the statement as meaning the charges add those potentials to an assumed background potential of zero everywhere.

 

[HalfLostAndSearching]

I can confirm that your understanding of electric potential is correct. However, in this specific scenario, the electric potential at the point midway between the two charges is indeed 0. This is because electric potential is a measure of the potential energy per unit charge, and at this point, the potential energy is balanced between the attractive force towards the positive charge and the repulsive force towards the negative charge. Therefore, the net potential energy experienced by a charge placed at this point is 0.

In other words, the electric potential at a point is not solely determined by the presence of a charge at that point, but also by the distribution of charges in the surrounding area. In this case, the two charges of the electric dipole create an equal and opposite electric field, resulting in a net electric potential of 0 at the point midway between them.

It is important to note that this does not mean that there is no electric field at this point. The electric field is still present and will still exert a force on any charged particle placed there. It is just that the net potential energy experienced by a charge at this point is 0.

I hope this clarifies why the electric potential at this point is 0. It is a result of the balance of forces created by the electric dipole.